The present invention is directed to a motor vehicle construction assembly. This construction assembly comprises a frame unit and a movable unit, e.g. an engine bonnet or a boot lid mounted on said frame unit for movement with respect thereto between a first and a second terminal operational position. At least part of this movement is subject to gravitational forces. At least one gas spring unit is provided fo balancing at least part of this gravitational force. The gas spring unit includes a cylinder member having an axis and two ends and defining a cavity therein. A piston rod member is sealingly guided through at least one of the ends. One of the members, namely the cylinder member and the piston rod member, is connected to one of the units, namely the frame unit and the movable unit. The other of the members is connected to the other of the units. The piston rod member is axially movable with respect to the cylinder member between a fully retracted operational position corresponding to said first terminal operational position of said movable unit and a fully extended operational position corresponding to said second terminal operational position of said movable unit. A pressurized gas contained within the cavity provides a biasing force for biasing said piston rod member towards said fully extended operational position.
Such a construction assembly is known, for example from German Offenlegungsschrift No. 26 19 176. In this known construction assembly a relatively small retaining force retains the piston rod member in its fully retracted operational position such that the biasing force acting on the piston rod member is at least partially compensated for and the gas spring exerts only small forces onto the frame unit and the movable unit when the movable unit is in its first terminal operational position. A small piston rod withdrawing force to be applied by hand is sufficient for overcoming this retaining force when the movable unit is to be moved into its second terminal operational position. After a short range of movement the retaining force ends so that the biasing force becomes fully effective for balancing the gravitational forces.
From German Offenlegungsschrift No. 28 51 366 it is known to withhold the piston rod in a position adjacent its innermost operational position after the manufacture of the gas spring so that the piston rod cannot be damaged during shipment and can easily be assembled with the frame unit and the movable unit. For withholding the piston rod in this position adjacent its innermost operational position a securing element is provided which is inserted by hand between the cylinder and the piston rod. During operation this securing element is removed.
In the known constructions no safety measures exist which could prevent a fast outward movement of the piston rod in case of an accident of the respective vehicle. Such fast outward movement can occur if e.g., the connections between the gas spring and the frame unit or the movable unit are broken. Moreover, there is no safety measure against an unintended opening of the movable unit, e.g. a bonnet, in case of an accident.